The development of new medical technologies and equipment has provided an increasing number of options available to doctors for the diagnosis and treatment of cardiovascular diseases. For example, ultrasound imaging technologies have enabled doctors to create and view a variety of images generated by one or more sensors inserted within a vasculature.
One ultrasound imaging technology that has been employed is intravascular ultrasound (IVUS). In IVUS imaging systems, an ultrasonic transducer assembly is attached to a distal end of a catheter. The catheter is carefully maneuvered through a patient's body, usually over a guide wire, to an area of interest such as within a coronary artery. The transducer assembly transmits ultrasound waves and receives echoes from those waves. The received echoes are then converted to electrical signals and transmitted to processing equipment where, for example, an image of the area of interest may be displayed.
Intracardiac echocardiography (ICE) is yet another imaging technology that has been used. ICE is similar to IVUS in that it uses a catheter with a transducer assembly at its distal end to facilitate imaging. However, ICE involves maneuvering the tip of the catheter, and hence transducer assembly, into the heart so that the walls of a heart chamber can be imaged. ICE catheters also typically include a steering mechanism that permits articulation of the distal end of the catheter.
IVUS and ICE catheters are relatively small because they need to be capable of traversing the inside of an artery. Consequently, the transducer assembly needs to be correspondingly small, while at the same time constructed to provide an imaging area that is as large as possible.
One known way to construct an ultrasound imaging catheter is to utilize a side firing element or array at the distal end of the catheter wherein the array is rotated about the longitudinal axis of the catheter. Another way is to arrange an array of transducer elements circumferentially around the longitudinal axis of the catheter. Yet another way is to arrange a linear array of transducer elements along the longitudinal axis of the catheter body. However, such arrangements typically provide a side looking view and it is not possible to view the area in front of the catheter assembly. In addition, implementations that utilize an array typically require additional circuitry to control multiple transducer elements.